The sentencing at London’s Old Bailey court fined Transport for London (TfL) £10 million and Tram Operations Limited (TOL) £4 million for their role in the November 2016 tragedy.
The tram passing through Croydon, south London, was carrying 69 passengers when it derailed.
Both transport operators had previously admitted to failing health and safety duties.
They were accused of “complacency” by the judge for ignoring poor lighting and other risks facing drivers in the Sandiland tunnel where the accident unfolded.
Prosecutor Jonathan Ashley-Norman had said during the trial that the derailment was an “accident waiting to happen”.
Tram driver Alfred Dorris was cleared of failing his duty in less than two hours last year.
While Dorris was going three times faster than he should have been at the south corner of the tunnel, he claimed he had become disorientated due to a lack of lighting and signage, among other factors.
Jean Smith, the mother of one of the victims, said that accountability may “bring some sense of peace”.
London’s Transport Commissioner Andy Lord said: “I apologise on behalf of everyone at Transport for London, both past and present, for this tragedy and for the pain, distress and suffering that all those affected have endured and continue to endure.
“We continually review our network and work with the wider tram industry to ensure we are running the safest possible service for our customers and to ensure that such a tragedy can never happen again.”
